JP2023051139A - air conditioner - Google Patents

Abstract

To reduce the number of components.SOLUTION: Refrigerant pipes 26a and 26b made of aluminum are connected to first connection parts of a flow divider 12 made of stainless steel. A refrigerant pipe 19a made of copper having a higher potential than that of aluminum is connected to a second connection part of the flow divider 12. A refrigerant flow passage from the refrigerant pipes 26a and 26b to the refrigerant pipe 19a via the flow divider 12 is formed.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to air conditioners.

Copper or a copper alloy is generally used as a material for refrigerant pipes of air conditioners. However, in recent years, part of the refrigerant pipe is made of aluminum or aluminum alloy in order to reduce weight and cost. However, aluminum has a higher ionization tendency than copper, and corrosion (potential corrosion) may occur in aluminum when the two are brought into contact with each other. In Patent Literature 1, a joint refrigerant pipe made of stainless steel is arranged at a joint portion between an aluminum refrigerant pipe and a copper refrigerant pipe so that aluminum is not corroded by condensed water adhering to the refrigerant pipe. The joint refrigerant pipe made of stainless steel is arranged on the side where the blower is provided from the connection pipe located closest to the blower among the plurality of connection pipes connecting the heat transfer pipes. . By doing so, it is possible to reduce the dripping of water droplets condensed on other connecting pipes onto the connecting refrigerant pipe.

WO2016/038865

However, according to the technique of Patent Literature 1, it is necessary to add a joint refrigerant pipe made of stainless steel as a new part, which increases the number of parts.

An object of the present disclosure is to provide an air conditioner with a small number of parts.

An air conditioner according to the present disclosure includes a first metal pipe, a second metal pipe having a higher potential than the first metal pipe, and a first part made of stainless steel including a first connection portion and a second connection portion. I have. The first metal pipe is connected to the first connection portion of the first component, the second metal pipe is connected to the second connection portion of the first component, and the first metal pipe is connected to the second connection portion of the first component. A refrigerant flow path is formed to the second metal pipe through one part, and the first part is any one of a filter, a muffler, a pressure reducing device, a refrigerant reservoir, and a flow divider.

According to the present disclosure, by connecting functional parts such as a filter made of stainless steel between the first metal and the second metal, there is no need to increase the number of parts for suppressing potential difference corrosion, and manufacturing costs can be reduced.

It is preferable that the first connecting portion is located above the second connecting portion. As a result, corrosion of the first metal pipe due to dropping of condensed water containing metal ions from the second metal pipe can be suppressed.

It is preferable that an end portion of the first connecting portion is inserted into the first metal pipe. As a result, peeling due to cooling after brazing is less likely to occur.

It further comprises a second part connected to the side of the first metal tube opposite to the first part, and a third part connected to the side of the second metal tube opposite to the first part. , the second part and the third part are any one of a heat exchanger, a filter, a muffler, a pressure reducing device, a refrigerant reservoir, a shut-off valve and a flow divider, and the first metal pipe is an aluminum refrigerant pipe wherein the second metal pipe is a refrigerant pipe made of copper, and between the second part and the third part, the bent portion of the first metal pipe is located more than the bent portion of the second metal pipe. is preferably less. As a result, there are few bending portions of aluminum, which is inferior in workability, which is advantageous in terms of manufacturing.

The first component is a filter, and the first metal pipe is a refrigerant pipe connected to a connection portion of the filter on the heat exchanger side, and connected to the first connection portion of the filter to connect the first metal pipe to the first connection portion of the filter. a first section extending upward from a connecting portion; a second section connected to the upper end portion of the first section, extending upward from the upper end portion and then extending downward in a different direction; and a third section that connects and extends downward. As a result, corrosion of the first metal pipe due to dropping of condensed water containing metal ions from the second metal pipe can be suppressed.

The first component may be a decompression device, the first metal tube may be made of aluminum, and the second metal tube may be made of copper. As a result, when it is preferable to position the decompression device as high as possible in order to shorten the electrical wiring of the air conditioner, the length of the aluminum pipe can be increased, which is advantageous in terms of cost.

The first component is a flow divider, the first metal pipe is an aluminum refrigerant pipe connected to an outdoor heat exchanger, and a pressure reducing device is provided on the opposite side of the flow divider from the outdoor heat exchanger. and a shutoff valve are provided, and it is preferable that both the piping between the flow divider and the pressure reducing device and the piping between the pressure reducing device and the shutoff valve are made of copper. As a result, the long refrigerant flow path from the flow divider through the decompression device to the closing valve is made of copper, which has excellent workability, which is advantageous in terms of manufacturing.

1 is a schematic configuration diagram of an air conditioner according to a first embodiment of the present disclosure; FIG. 2 is a perspective view of an outdoor heat exchanger and some refrigerant pipes included in the air conditioner shown in FIG. 1, and an enlarged view of the vicinity of a filter; FIG. 3 is a front view of the outdoor heat exchanger and some refrigerant pipes shown in FIG. 2; FIG. FIG. 3 is a partial side view of the outdoor heat exchanger and some refrigerant pipes shown in FIG. 2; FIG. 4 is an enlarged cross-sectional view of a joining portion between a stainless steel filter and an aluminum refrigerant pipe; FIG. 4 is a partial side view of an outdoor heat exchanger and some refrigerant pipes included in an air conditioner according to a second embodiment of the present disclosure; FIG. 11 is a partial side view of an outdoor heat exchanger and some refrigerant pipes included in an air conditioner according to a third embodiment of the present disclosure; FIG. 11 is a partial side view of an outdoor heat exchanger and some refrigerant pipes included in an air conditioner according to a fourth embodiment of the present disclosure; FIG. 11 is a partial side view of an outdoor heat exchanger and some refrigerant pipes included in an air conditioner according to a fifth embodiment of the present disclosure; FIG. 11 is a side view of the vicinity of a muffler included in an air conditioner according to a sixth embodiment of the present disclosure; FIG. 20 is a side view of the vicinity of an accumulator included in an air conditioner according to a seventh embodiment of the present disclosure;

<First embodiment>
The air conditioner 1 according to the first embodiment of the present disclosure will be described below. An air conditioner 1 shown in FIG. 1 includes an indoor unit 2 installed indoors and an outdoor unit 3 installed outdoors. The indoor unit 2 and the outdoor unit 3 are connected to each other by refrigerant pipes 19 .

The outdoor unit 3 includes a compressor 5 that compresses the refrigerant to generate a high-temperature and high-pressure gas refrigerant, filters 14 and 20, a liquid receiver (a type of refrigerant storage device in the present disclosure) 13, and an electric expansion device that decompresses the refrigerant. A valve 7, an outdoor heat exchanger 8, an accumulator (a kind of refrigerant storage device in the present disclosure) 11, a muffler 15, a four-way switching valve 16, a gas shutoff valve 17, and a liquid shutoff valve 18 are arranged. An indoor heat exchanger 6 is arranged in the indoor unit 2 . These multiple element parts are connected by refrigerant pipes 19 to form the refrigerant circuit 4 . The electric expansion valve 7 is provided with a first connecting pipe 7a and a second connecting pipe 7b. The first connecting pipe 7a and the second connecting pipe 7b are attached to the main body of the electric expansion valve 7 (the portion other than the first connecting pipe 7a and the second connecting pipe 7b) by brazing.

The indoor heat exchanger 6 exchanges heat between the refrigerant and the indoor air. An indoor fan 9 is arranged in the vicinity of the indoor heat exchanger 6 for blowing indoor air to the indoor heat exchanger 6 and sending conditioned air indoors. The compressor 5 compresses the low-pressure gas refrigerant and discharges high-pressure gas refrigerant. The compressor 5 has a suction portion 5a and a discharge portion 5b. Low-pressure gas refrigerant is sucked from the suction portion 5a, and high-pressure gas refrigerant is discharged in the direction of arrow D from the discharge portion 5b. The electric expansion valve 7 is arranged between the outdoor heat exchanger 8 and the indoor heat exchanger 6 in the refrigerant pipe 19 of the refrigerant circuit 4, and expands and decompresses the refrigerant that has flowed thereinto. The filters 14 and 20 are also rectifying members that remove fine dust from the refrigerant, reduce air bubbles, and regulate turbulence in the flow of the refrigerant. The noise generated by the electric expansion valve 7 can be reduced by making the air bubbles fine. The liquid receiver 13 stores excess refrigerant due to fluctuations in the heat load. The outdoor heat exchanger 8 exchanges heat between the refrigerant and the outdoor air. An outdoor fan 10 for blowing outdoor air to the outdoor heat exchanger 8 is provided near the outdoor heat exchanger 8 .

A flow divider 12 (first component in the present embodiment) is arranged at the end of the outdoor heat exchanger 8 on the electric expansion valve 7 side. The flow divider 12 is a functional component provided with a branch flow path inside. The flow divider 12 includes two refrigerant pipes 26a and 26b (first metal pipes in this embodiment) extending from the outdoor heat exchanger 8 (see FIGS. 2 and 4) and one pipe connected to the filter 14. is connected to the refrigerant pipe 19a (second metal pipe in this embodiment). The filter 14 and the first connection pipe 7a of the electric expansion valve 7 are connected by a refrigerant pipe 19b. The second connection pipe 7b of the electric expansion valve 7 and the liquid receiver 13 are connected by a refrigerant pipe 19c. The liquid receiver 13, the filter 20 and the liquid closing valve 18 are also connected by a refrigerant pipe 19c. Also, an accumulator 11 is connected to the refrigerant pipe 19d on the intake side of the compressor 5 for sending gas to the compressor 5 in preference to liquid. A muffler 15 for reducing pressure pulsation of the refrigerant discharged from the compressor 5 is connected to the refrigerant pipe 19 e on the discharge side of the compressor 5 .

The refrigerant pipe 19 is connected to a four-way switching valve 16 for switching refrigerant flow paths, a gas shutoff valve 17 and a liquid shutoff valve 18 . By switching the four-way switching valve 16, the flow of the refrigerant is reversed, the refrigerant discharged from the compressor 5 is supplied to either the outdoor heat exchanger 8 or the indoor heat exchanger 6, and cooling operation and heating operation are performed. It is possible to switch. The gas shut-off valve 17 and the liquid shut-off valve 18 are made of brass and serve to open or close the refrigerant path.

During the heating operation of the air conditioner 1, the four-way switching valve 16 is switched as indicated by the solid line in FIG. 1 to flow the refrigerant in the direction indicated by the solid line arrow. As a result, the high-pressure gas refrigerant discharged from the compressor 5 in the direction of arrow D passes through the muffler 15 and the four-way switching valve 16 , then passes through the gas shut-off valve 17 and enters the indoor heat exchanger 6 . The high-pressure gas refrigerant releases heat in the process of becoming high-pressure liquid refrigerant in the indoor heat exchanger 6 . The high-pressure liquid refrigerant reaches the electric expansion valve 7 via the opened liquid closing valve 18 and is decompressed by the electric expansion valve 7 . The decompressed refrigerant reaches the outdoor heat exchanger 8, absorbs heat in the outdoor heat exchanger 8, and becomes low-pressure gas refrigerant. Low-pressure gas refrigerant is sucked into the compressor 5 through the four-way switching valve 16 and the accumulator 11 . During heating operation, the indoor heat exchanger 6 functions as a radiator, and the outdoor heat exchanger 8 functions as a heat absorber.

On the other hand, during cooling operation, the flow of the refrigerant is reversed by switching the four-way switching valve 16 as indicated by the dotted line in FIG. 1, and the refrigerant flows in the direction indicated by the dotted arrow. As a result, the high-pressure gas refrigerant discharged from the compressor 5 in the direction of arrow D enters the outdoor heat exchanger 8 after passing through the muffler 15 and the four-way switching valve 16 . The high-pressure gas refrigerant releases heat in the process of becoming high-pressure liquid refrigerant in the outdoor heat exchanger 8 . The high-pressure liquid refrigerant reaches the electric expansion valve 7 and is decompressed by the electric expansion valve 7 . The decompressed refrigerant reaches the indoor heat exchanger 6 through the opened liquid closing valve 18, absorbs heat in the indoor heat exchanger 6, and becomes a low-pressure gas refrigerant. Low-pressure gas refrigerant is sucked into the compressor 5 through the gas shutoff valve 17 , the four-way switching valve 16 and the accumulator 11 . During cooling operation, the indoor heat exchanger 6 functions as a heat absorber, and the outdoor heat exchanger 8 functions as a radiator.

As shown in FIGS. 2 and 3, the outdoor heat exchanger 8 includes a plurality of flat fins 21 stacked at predetermined intervals and a plurality of through holes provided in each fin 21. heat transfer tubes 22 (only one is shown in dashed lines in FIG. 3). Each heat transfer tube 22 is bent into an L shape, and the outdoor heat exchanger 8 has a substantially L shape when viewed from above. Except for the ends that serve as the refrigerant inlet and outlet (two places each) to the outdoor heat exchanger 8, the ends provided with the openings of the heat transfer tubes 22 are formed by U-bends 23 so that the openings of other heat transfer tubes 22 are separated. It is connected with the provided end. Thus, the outdoor heat exchanger 8 of the present embodiment has two flow paths through which the refrigerant passes. Fins 21, heat transfer tubes 22, and U-bends 23 are made of aluminum or an aluminum alloy (collectively referred to simply as "made of aluminum" in this disclosure). A hairpin tube may be used as the heat transfer tube.

An end plate 25 made of a steel plate or the like is arranged further outside the outermost fins 21 . The end plate 25 is penetrated by the heat transfer tube 22 , and the heat transfer tube 22 is connected to the U bend 23 outside the end plate 25 . Refrigerant pipes leading to the two flow paths configured in the outdoor heat exchanger 8 are connected to the ends of the heat transfer tubes 22 to which the U-bends 23 are not connected. 2 and 4 show two refrigerant pipes 26a and 26b connected to the flow divider 12 of them. In the following description, the vertical relationship will be described with reference to FIG.

In this embodiment, the refrigerant pipes 26a and 26b are made of aluminum, and the flow divider 12 is made of stainless steel. Refrigerant pipes 19a, 19b, and 19c ahead of the flow divider 12 are made of copper or a copper alloy having a potential higher than that of aluminum (collectively referred to as "copper" in the present disclosure). The filter 14, receiver 13, and filter 20 are also made of copper, the main body of the electric expansion valve 7 is made of stainless steel, and the first connecting pipe 7a and the second connecting pipe 7b are made of copper. Referring to FIG. 2, the flow divider 12 includes two first connections 12a, 12b and one second connection 12c. The first connecting portions 12a, 12b are respectively joined to the refrigerant pipes 26a, 26b by brazing. The second connecting portion 12c is joined to the refrigerant pipe 19a by brazing. Thereby, a refrigerant flow path is formed from the refrigerant pipes 26 a and 26 b to the refrigerant pipe 19 a via the flow divider 12 . In the flow divider 12, a branched flow path is formed that connects the first connection portions 12a, 12b and the second connection portion 12c. In this embodiment, the first connection portions 12a and 12b are above the second connection portion 12c.

Thus, in the air conditioner 1 according to the present embodiment, the flow divider 12 as a functional component is made of stainless steel, and the aluminum refrigerant pipes 26a and 26b and the copper refrigerant pipe 19a are attached to the flow divider 12. are spliced. As a result, the refrigerant pipes 26a and 26b made of aluminum and the refrigerant pipe 19a made of copper are not directly joined, and the potential difference corrosion of the refrigerant pipes 26a and 26b can be suppressed. Further, by making the flow divider 12 as an existing functional part made of stainless steel and interposing it between the refrigerant pipes 26a, 26b and the refrigerant pipe 19a, new parts are increased for suppressing potential difference corrosion of the refrigerant pipes 26a, 26b. This eliminates the need and reduces manufacturing costs. Moreover, since the first connecting portions 12a and 12b are located above the second connecting portion 12c, even if condensed water containing copper ions adheres and falls on the surface of the copper refrigerant pipe 19a due to condensation, the condensed water will not adhere to the aluminum refrigerant pipes 26a and 26b. Therefore, potential difference corrosion of the refrigerant pipes 26a and 26b can be more effectively suppressed.

In addition, in the air conditioner 1 according to the present embodiment, the refrigerant pipes 26a and 26b between the flow divider 12 and the outdoor heat exchanger 8 are made of aluminum. Long refrigerant pipes 19a, 19b, and 19c up to the valve 18 are made of copper. As described above, in this embodiment, most of the refrigerant pipes from the outdoor heat exchanger 8 to the liquid closing valve 18 are made of copper, which has excellent workability, which is advantageous in terms of manufacturing.

Here, the details of the connection between the flow divider 12 and the refrigerant pipe will be described with reference to FIG. 5 . Although the connection between the first connection portion 12a and the refrigerant pipe 26a will be described below as an example, the connection between the first connection portion 12b and the refrigerant pipe 26b is also the same. As shown in FIG. 5, the vicinity of the lower end (the right end in FIG. 5) of the refrigerant pipe 26a is enlarged in diameter. Its inner diameter is slightly larger than the outer diameter of the first connecting portion 12a. The outer diameter and inner diameter of the first connection portion 12a are the same as the outer diameter and inner diameter of the non-expanded section of the refrigerant pipe 26a, respectively. The vicinity of the upper end portion (the left end portion in FIG. 5) of the first connection portion 12a is inserted near the enlarged lower end portion of the refrigerant pipe 26a. The vicinity of the upper end portion of the first connection portion 12a and the vicinity of the expanded lower end portion of the refrigerant pipe 26a are joined by brazing as described above, and the brazing material 28 is interposed between them.

Aluminum has a larger coefficient of linear expansion than stainless steel. The solidification temperature of the brazing material 28 in the brazing process is as high as about 580.degree. The amount of shrinkage inward of the refrigerant pipe 26a in the process of cooling the aluminum refrigerant pipe 26a and the stainless steel first connection portion 12a from the solidification temperature to room temperature is the amount of contraction inward of the first connection portion 12a. bigger than In the present embodiment, since the vicinity of the upper end of the first connecting portion 12a is inserted into the vicinity of the lower end of the refrigerant pipe 26a, the refrigerant pipe 26a tends to contract greatly inward during the cooling process after the brazing process. The brazing filler metal 28 sandwiched between the vicinity of the lower end portion and the vicinity of the upper end portion of the first connecting portion 12a, which shrinks inwardly to a small extent, is subjected to a stress that causes the brazing filler metal 28 to contract in the radial direction. Therefore, compared with the case where the vicinity of the lower end of the refrigerant pipe 26a is inserted in the vicinity of the upper end of the first connecting portion 12a, peeling at the brazed portion is less likely to occur, and the reliability of the joint can be improved.

Although copper has a higher linear expansion coefficient than many stainless steel materials, it has a lower linear expansion coefficient than some stainless steel materials. Therefore, when the linear expansion coefficient of the stainless steel material of the flow divider 12 is larger than the linear expansion coefficient of the copper material of the refrigerant pipe 19a, the refrigerant pipe 26a is preferably inserted into the first connection portion 12a, and vice versa. , the first connecting portion 12a is preferably inserted into the refrigerant pipe 26a. Also in the embodiments described below, the brazing joints between the stainless steel functional parts and the aluminum refrigerant pipes, and the brazing joints between the stainless steel functional parts and the copper refrigerant pipes are the same as the present invention. It has the same structure as the embodiment.

<Second embodiment>
Next, an air conditioner according to a second embodiment of the present disclosure will be described. The air conditioner according to this embodiment is the same as that of the first embodiment except for the configuration from the flow divider to the filter adjacent thereto. Therefore, the differences from the first embodiment will be mainly described below.

In FIG. 6, the flow divider 32 (second part in this embodiment) is made of aluminum, and the filter 34 (first part in this embodiment) is made of stainless steel. A refrigerant pipe 39a (first metal pipe in this embodiment) between the flow divider 32 and the filter 34 is made of aluminum. A refrigerant pipe 19b (second metal pipe in this embodiment) between the filter 34 and the electric expansion valve 7 (third component in this embodiment) is made of copper as in the first embodiment. The filter 34 includes one first connection portion 34a at its lower end and one second connection portion 34b at its upper end. The first connecting portion 34a is joined to the refrigerant pipe 39a by brazing. The second connecting portion 34b is joined to the refrigerant pipe 19b by brazing. Thereby, a refrigerant flow path is formed from the refrigerant pipe 39a through the filter 34 to the refrigerant pipe 19b. A mesh member having a large number of fine holes is arranged in the filter 34 .

As described above, in the air conditioner according to the present embodiment, the filter 34 as a functional component is made of stainless steel, and the aluminum refrigerant pipe 39a and the copper refrigerant pipe 19b are joined to the filter 34 . As a result, the refrigerant pipe 39a made of aluminum and the refrigerant pipe 19b made of copper are not directly joined, and the potential difference corrosion of the refrigerant pipe 39a can be suppressed. In addition, by interposing the filter 34 as an existing functional part made of stainless steel between the refrigerant pipe 39a and the refrigerant pipe 19b, there is no need to increase the number of new parts for suppressing the potential difference corrosion of the refrigerant pipe 39a. You can keep costs down.

Further, in the air conditioner according to the present embodiment, the aluminum refrigerant pipe 39a between the flow divider 32 and the filter 34 is substantially U-shaped, and there is only one bending portion. On the other hand, as can be seen from FIG. 6, the refrigerant pipe 19b between the filter 34 and the electric expansion valve 7 has a vertical section immediately above the filter 34, an obliquely extending section, and an electric expansion valve 7 It has a shape in which it is connected to the vertical section immediately below, and there are two bending points. As described above, in the present embodiment, since the aluminum refrigerant pipe 39a, which has poor machinability, has few parts to be machined between the flow divider 32 and the electric expansion valve 7, there is an advantage that the production is easy. In addition, between the outdoor heat exchanger 8 and the liquid closing valve 18, the bent portions of the aluminum refrigerant pipes 26a, 26b, and 39a between the filter 34 and the outdoor heat exchanger 8 are liquid-closed from the filter 34. Since there are fewer bends than the copper refrigerant pipes 19b and 19c between the valve 18 and the valve 18, manufacturing is facilitated. Moreover, at least part of the effects described in the above-described first embodiment can also be obtained according to the present embodiment.

<Third Embodiment>
Next, an air conditioner according to a third embodiment of the present disclosure will be described. The air conditioner according to this embodiment is the same as that of the second embodiment except for the configuration from the filter to the electric expansion valve. Therefore, the differences from the second embodiment will be mainly described below.

In FIG. 7, the filter 35 (the second component in this embodiment) is made of aluminum, and the main body of the electric expansion valve 37 (the first component in this embodiment) is made of stainless steel. It is made of aluminum, and the second connecting pipe 37b is made of copper. A refrigerant pipe 39b (first metal pipe in this embodiment) between the filter 35 and the electric expansion valve 37 is made of aluminum. A refrigerant pipe 19c (second metal pipe in this embodiment) between the electric expansion valve 37 and the liquid receiver 13 (third component in this embodiment) is made of copper as in the first embodiment. A first connection portion 37a of the electric expansion valve 37 is joined to the refrigerant pipe 39b by brazing. The second connecting portion 37b is joined to the refrigerant pipe 19c by brazing. Thus, a refrigerant flow path is formed from the refrigerant pipe 39b to the refrigerant pipe 19c via the electric expansion valve 37. As shown in FIG. A stepping motor is arranged in the electric expansion valve 37 so that the degree of opening and closing can be adjusted almost steplessly.

As described above, in the air conditioner according to the present embodiment, the main body of the electric expansion valve 37 as a functional component is made of stainless steel, and the aluminum refrigerant pipe 39b and the copper refrigerant pipe 19c are respectively connected to the electric expansion valve 37. are joined to a first connecting pipe 37a made of aluminum and a second connecting pipe 37b made of copper. As a result, the refrigerant pipe 39b made of aluminum and the refrigerant pipe 19c made of copper are not directly joined, and the potential difference corrosion of the refrigerant pipe 39b can be suppressed. In addition, by making the main body of the electric expansion valve 37 as an existing functional part made of stainless steel and interposing it between the refrigerant pipe 39b and the refrigerant pipe 19c, the number of new parts is increased to suppress potential difference corrosion of the refrigerant pipe 39a. This eliminates the need and reduces manufacturing costs.

In addition, in the air conditioner according to the present embodiment, the electric expansion valve 37, which is a decompression device, is a functional component (flow divider 32, It is arranged at a position higher than the filter 35, receiver 13 and filter 20). An electronic board (not shown) connected to the electric expansion valve 37 via electrical wiring is often arranged at a relatively high position inside the outdoor unit 3 . Therefore, the electric expansion valve 37 is made of stainless steel, and the refrigerant pipes 39a and 39b between the outdoor heat exchanger 8 and the first connection pipe 37a are made of aluminum. The electric wiring can be shortened, which is advantageous in terms of cost.

Furthermore, in the air conditioner according to the present embodiment, as can be seen from FIG. It has a shape in which a section extending vertically is connected to a vertical section immediately below the electric expansion valve 37, and there are two bending points. On the other hand, the copper refrigerant pipe 19c between the electric expansion valve 37 and the liquid receiver 13 has a vertical section immediately below the second connecting pipe 37b, a section extending obliquely forward and downward, and a section extending obliquely downward rearward. It has a shape in which a section extending vertically is connected to a vertical section immediately above the liquid receiver 13 (see FIG. 3), and there are three bending points. As described above, in the present embodiment, since the aluminum refrigerant pipe 39b, which has poor machinability, has few parts to be machined between the filter 35 and the liquid receiver 13, there is an advantage in that manufacturing is easy. Also, between the outdoor heat exchanger 8 and the liquid shutoff valve 18, the aluminum refrigerant pipes 26a, 26b, 39a, and 39b between the electric expansion valve 37 and the outdoor heat exchanger 8 are electrically bent. Since there are fewer bends than the copper refrigerant pipe 19c between the expansion valve 37 and the liquid shut-off valve 18, manufacturing is facilitated. Also, according to this embodiment, at least part of the effects described in the above-described first and second embodiments can be obtained.

<Fourth Embodiment>
Next, an air conditioner according to a fourth embodiment of the present disclosure will be described. The air conditioner according to this embodiment is the same as the third embodiment except for the configuration related to the electric expansion valve. Therefore, the differences from the third embodiment will be mainly described below.

In FIG. 8, the filter 35 (second component in this embodiment) is made of aluminum, and the electric expansion valve 38 (first component in this embodiment) has a main body, a first connecting pipe 38a and a second connecting pipe 38b. Made of stainless steel. A refrigerant pipe 39b (first metal pipe in this embodiment) between the filter 35 and the electric expansion valve 38 is made of aluminum. A refrigerant pipe 19c (second metal pipe in this embodiment) between the electric expansion valve 38 and the liquid receiver 13 (third component in this embodiment) is made of copper as in the first embodiment. A first connection portion 38a of the electric expansion valve 38 is joined to the refrigerant pipe 39b by brazing. The second connecting portion 38b is joined to the refrigerant pipe 19c by brazing. Thus, a refrigerant flow path is formed from the refrigerant pipe 39b to the refrigerant pipe 19c via the electric expansion valve 38. As shown in FIG.

Also in this embodiment, the main body of the electric expansion valve 38 as a functional component is made of stainless steel, and the aluminum refrigerant pipe 39b and the copper refrigerant pipe 19c are respectively the stainless steel first connecting pipes of the electric expansion valve 37. 38a and a second connecting pipe 38b made of stainless steel. Thereby, it is possible to suppress potential difference corrosion of the refrigerant pipe 39b. Moreover, there is no need to increase the number of new parts for suppressing the potential difference corrosion of the refrigerant pipe 39a, and the manufacturing cost can be suppressed.

Further, in this embodiment, the main body of the electric expansion valve 38 is made of stainless steel, and the first connecting pipe 38a and the second connecting pipe 38b made of the same stainless steel as the main body are joined thereto by brazing. , both brazing processes can be performed simultaneously, and the manufacturing process of the electric expansion valve 38 can be simplified. Further, since the second connecting pipe 38b is made of stainless steel instead of copper, even if the condensed water adhering to the surface of the second connecting pipe 38b adheres to the refrigerant pipe 39b made of aluminum, etc., the condensed water , the refrigerant pipe 39b and the like are less susceptible to potential difference corrosion. Also, according to this embodiment, at least part of the effects described in the above-described first to third embodiments can be obtained.

<Fifth Embodiment>
Next, an air conditioner according to a fifth embodiment of the present disclosure will be described. The air conditioner according to this embodiment is the same as that of the second embodiment except for the configuration from the flow divider to the electric expansion valve. Therefore, the differences from the second embodiment will be mainly described below.

In FIG. 9, the filter 45 (first component in this embodiment) is made of stainless steel. A refrigerant pipe 49a (first metal pipe in this embodiment) between the filter 45 and the flow divider 32 (second part in this embodiment) is made of aluminum. A refrigerant pipe 49b (second metal pipe in this embodiment) between the filter 45 and the electric expansion valve 7 (third component in this embodiment) is made of copper as in the first embodiment. The filter 45 includes one first connection portion 45a at its upper end and one second connection portion 45b at its lower end. The first connecting portion 45a is joined to the refrigerant pipe 49a by brazing. The second connecting portion 45b is joined to the refrigerant pipe 49b by brazing. Thereby, a refrigerant flow path is formed from the refrigerant pipe 49a through the filter 45 to the refrigerant pipe 49b.

Thus, in the air conditioner according to the present embodiment, the filter 45 as a functional component is made of stainless steel, and the aluminum refrigerant pipe 49a and the copper refrigerant pipe 49b are joined to the filter 45. As a result, the refrigerant pipe 49a made of aluminum and the refrigerant pipe 49b made of copper are not directly joined, and the potential difference corrosion of the refrigerant pipe 49a can be suppressed. In addition, by making the filter 45 as an existing functional part made of stainless steel and interposing it between the refrigerant pipe 49a and the refrigerant pipe 49b, there is no need to increase new parts for suppressing the potential difference corrosion of the refrigerant pipe 49a. You can keep costs down.

Further, in the present embodiment, the refrigerant pipe 49a connected to the first connecting pipe 45a on the outdoor heat exchanger 8 side of the filter 45 includes three sections described below. The first section PA is connected to the first connection portion 45a of the filter 45 and extends upward from the first connection portion 45a. The second section PB is connected to the upper end portion of the first section PA, extends upward from the upper end portion, changes direction and extends downward, and has a U-shape. The third section PC is connected to the lower end portion of the second section PB and extends downward. By configuring the refrigerant pipe 49a to include the three sections PA, PB, and PC as described above, the refrigerant pipes 26a and 26b and the flow divider 32 are arranged near the lower end of the outdoor heat exchanger 8. Even in this case, the upper end of the filter 45 may be the connection point with the aluminum refrigerant pipe 49a, and the lower end of the filter 45 may be the connection point with the copper refrigerant pipe 49b. Corrosion of the refrigerant pipe 49a due to dropping of condensed water containing copper ions in the refrigerant pipe 49b can thereby be suppressed. Although the first section PA and the third section PC extend in the vertical direction in the example shown in FIG. 9, the first section PA and the third section PC do not necessarily extend in the vertical direction. may be inclined with respect to Also, according to this embodiment, at least part of the effects described in the first to fourth embodiments can be obtained.

<Sixth embodiment>
Next, an air conditioner according to a sixth embodiment of the present disclosure will be described. The air conditioner according to this embodiment is the same as the first embodiment except for the configuration from the outdoor heat exchanger 8 to the muffler (corresponding to the muffler 15 shown in FIG. 1). Therefore, the differences from the first embodiment will be mainly described below.

In FIG. 10, the muffler 55 (first component in this embodiment) is made of stainless steel. The muffler 55 includes one first connection portion 55a at its upper end and one second connection portion 55b at its lower end. The first connecting portion 55a is joined to the refrigerant pipe 59e (the first metal pipe in this embodiment) by brazing. The second connecting portion 55b is joined to the refrigerant pipe 57 (second metal pipe in this embodiment) by brazing. The refrigerant pipe 59 e is made of aluminum and is connected to the outdoor heat exchanger 8 via the four-way switching valve 16 . The four-way switching valve 16 is made of stainless steel. A refrigerant pipe 57 is made of copper and is connected to the compressor 5 . Thereby, a refrigerant flow path from the refrigerant pipe 59e to the refrigerant pipe 57 via the muffler 55 is formed.

Thus, in the air conditioner according to the present embodiment, the muffler 55 as a functional component is made of stainless steel, and the aluminum refrigerant pipe 59e and the copper refrigerant pipe 57 are joined to the muffler 55. As a result, the refrigerant pipe 59e made of aluminum and the refrigerant pipe 57 made of copper are not directly joined, and the potential difference corrosion of the refrigerant pipe 59e can be suppressed. In addition, by making the muffler 55 as an existing functional part made of stainless steel and interposing it between the refrigerant pipe 59e and the refrigerant pipe 57, there is no need to increase the number of new parts for suppressing the potential difference corrosion of the refrigerant pipe 59e. You can keep costs down. Also, according to this embodiment, at least part of the effects described in the first to fifth embodiments can be obtained.

<Seventh embodiment>
Next, an air conditioner according to a seventh embodiment of the present disclosure will be described. The air conditioner according to this embodiment is the same as the first embodiment except for the configuration from the outdoor heat exchanger 8 to the accumulator (corresponding to the accumulator 11 shown in FIG. 1). Therefore, the differences from the first embodiment will be mainly described below.

In FIG. 11, the accumulator 61 (first component in this embodiment) is made of stainless steel. The accumulator 61 includes one first connecting portion 61a at its upper end and one second connecting portion 61b at its upper end. The first connecting portion 61a is joined to the refrigerant pipe 69d (the first metal pipe in this embodiment) by brazing. The second connection portion 61b is joined to the refrigerant pipe 67 (second metal pipe in this embodiment) by brazing. The refrigerant pipe 69 d is made of aluminum and is connected to the outdoor heat exchanger 8 via the compressor 5 , the muffler 15 and the four-way switching valve 16 . The compressor 5 and the muffler 15 may be made of aluminum or stainless steel. The four-way switching valve 16 is made of stainless steel. A refrigerant pipe 67 is made of copper and is connected to the four-way switching valve 16 . Thereby, a refrigerant flow path is formed from the refrigerant pipe 69 d to the refrigerant pipe 67 via the accumulator 61 .

Thus, in the air conditioner according to the present embodiment, the accumulator 61 as a functional component is made of stainless steel, and the aluminum refrigerant pipe 69d and the copper refrigerant pipe 67 are joined to the accumulator 61. As a result, the refrigerant pipe 69d made of aluminum and the refrigerant pipe 67 made of copper are not directly joined, and the potential difference corrosion of the refrigerant pipe 69d can be suppressed. In addition, by making the accumulator 61 as an existing functional part made of stainless steel and interposing it between the refrigerant pipe 69d and the refrigerant pipe 67, there is no need to increase the number of new parts for suppressing the potential difference corrosion of the refrigerant pipe 69d. You can keep costs down. Also, according to this embodiment, at least part of the effects described in the above-described first to sixth embodiments can be obtained.

<Modification>
In the first to fifth embodiments, the liquid receiver 13 is made of stainless steel, the refrigerant pipe between the liquid receiver 13 and the outdoor heat exchanger 8 is made of aluminum, and between the liquid receiver 13 and the liquid closing valve 18 , the refrigerant pipe may be made of copper. Further, in the first to fifth embodiments, the filter 20 is made of stainless steel, the refrigerant pipe between the filter 20 and the outdoor heat exchanger 8 is made of aluminum, and the refrigerant pipe between the filter 20 and the liquid closing valve 18 is It may be made of copper. In the above embodiment, the first metal tube is made of aluminum and the second metal tube is made of copper. However, if the material of the second metal tube has a higher potential than the material of the first metal tube, A metal other than aluminum may be used as the material, and a metal other than copper may be used as the material of the second metal pipe.

Although the above-described embodiments relate to functional components and refrigerant piping within an outdoor heat exchanger, the present disclosure is also applicable to functional components and refrigerant piping within an indoor heat exchanger. For example, in the indoor unit, the heat transfer pipes of the front heat exchanger and the refrigerant pipes connected thereto are made of aluminum, and the heat transfer pipes of the rear heat exchanger and the refrigerant pipes connected thereto are made of copper. of reheat dehumidification valve (pressure reducing valve) may be connected.

In the first to fifth embodiments, any one or more parts other than the electric expansion valve 7 between the outdoor heat exchanger 8 and the liquid closing valve 18 can be omitted. A muffler may be arranged between the outdoor heat exchanger 8 and the liquid shutoff valve 18 , and a filter may be arranged between the outdoor heat exchanger 8 and the gas shutoff valve 17 . The portions described as being joined by brazing in the above embodiment may be joined by a method other than brazing such as welding. The first component may be entirely made of stainless steel, or may be partially made of stainless steel. For example, the first connection portion is made of the same metal as the first metal pipe, the second connection portion is made of the same metal as the second metal pipe, and the portion connecting the first connection portion and the second connection portion is made of stainless steel. may consist of

Although the embodiments have been described above, it will be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the claims.

1 air conditioner 2 indoor unit 3 outdoor unit 6 indoor heat exchanger 7 electric expansion valve 7a first connection pipe 7b second connection pipe 8 outdoor heat exchanger 11 accumulator 12 flow divider 12a, 12b first connection portion 12c second connection Part 13 Liquid receiver 14, 20 Filter 15 Muffler 16 Four-way switching valve 17 Gas shutoff valve 18 Liquid shutoff valve 19 (19a, 19b, 19c) Refrigerant piping 26a, 26b Refrigerant piping

Claims (7)

a first metal tube;
a second metal tube having a higher potential than the first metal tube;
a stainless steel first part including a first connection and a second connection;
The first metal pipe is connected to the first connecting portion of the first component, the second metal pipe is connected to the second connecting portion of the first component, and the first metal pipe is connected to the first component. A coolant flow path is formed to the second metal pipe through
The air conditioner, wherein the first part is any one of a filter, a muffler, a pressure reducing device, a refrigerant reservoir and a flow divider. 2. The air conditioner according to claim 1, wherein said first connecting portion is located above said second connecting portion. 3. The air conditioner according to claim 1, wherein an end portion of said first connecting portion is inserted into said first metal pipe. It further comprises a second part connected to the side of the first metal tube opposite to the first part, and a third part connected to the side of the second metal tube opposite to the first part. ,
wherein the second part and the third part are any one of a heat exchanger, a filter, a muffler, a pressure reducing device, a refrigerant reservoir, a shut-off valve and a flow divider,
The first metal pipe is an aluminum refrigerant pipe, the second metal pipe is a copper refrigerant pipe,
The air according to any one of claims 1 to 3, wherein between the second part and the third part, the first metal tube has less bending points than the second metal tube. harmony machine. the first component is a filter;
The first metal pipe is
A refrigerant pipe connected to a connection portion on the heat exchanger side of the filter,
a first section connected to the first connection portion of the filter and extending upward from the first connection portion; The air conditioner according to any one of claims 1 to 4, comprising an extending second section and a third section connecting to a lower end portion of the second section and extending downward. The air conditioner according to any one of claims 1 to 4, wherein the first component is a decompression device, the first metal pipe is made of aluminum, and the second metal pipe is made of copper. The first component is a flow divider, the first metal pipe is an aluminum refrigerant pipe connected to an outdoor heat exchanger, and a pressure reducing device is provided on the opposite side of the flow divider from the outdoor heat exchanger. and a shut-off valve are provided,
The air conditioner according to any one of claims 1 to 4, wherein the piping between the flow divider and the decompression device and the piping between the decompression device and the closing valve are both made of copper.

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